JP4874834B2 - Seamless belt manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a seamless belt manufactured by thermoforming. This seamless belt is useful as a functional belt such as a conveyance belt or a transfer belt used in an image forming apparatus such as an electrophotographic copying machine or a printer.

  In recent years, high speed and high image quality have been demanded for transfer conveyance belts, intermediate transfer belts, transfer fixing belts, and photosensitive belts used in image forming apparatuses such as electrophotographic copying machines, printers, facsimiles, and composite machines thereof. Therefore, seamlessness is desired for these functional belts. The production of a seamless belt has been performed by spreading a resin solution on the inner surface of a cylindrical mold, performing rotational molding and thermoforming, and humidifying the mold by induction heating (see, for example, Patent Document 1). .

Conventionally, as a material for a seamless belt, a plastic material has been used for reasons such as good moldability and light weight, and this plastic material has excellent heat resistance, mechanical strength, and environmental resistance. Therefore, a polyimide seamless belt using a polyimide resin has been studied. Moreover, as a characteristic requested | required of the belt material used for an electrostatic transfer system, it has what is called a medium resistance whose surface resistance value is about 10 < ⁸ > -10 < ¹³ > ohm * cm. Therefore, a method of incorporating a large amount of carbon black in the polyimide resin is generally used (see, for example, Patent Document 2).

JP 2004-181731 A JP-A-10-63115

  However, the manufacturing method described in the above prior art has the following problems. That is, since the synthesis and film formation of polyimide resin go through complicated processes, problems due to the aggregation of carbon black occur, and as a result, there is a problem that the electrical resistance value decreases due to variation in resistivity and electrical load during use. is there. Such a decrease in the electric resistance value causes an excessive current to flow through the belt during transfer. Therefore, when the belt is used as an intermediate transfer belt, a trouble on the image such as retransfer of toner once transferred occurs.

  In addition, the present inventors have discovered that the surface resistivity of the dried film becomes non-uniform because the solution resin developed on the inner surface of the cylindrical mold is not uniformly heated. I wanted a solution.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a seamless belt manufacturing method capable of uniformly heating a solution resin developed on the inner surface of a cylindrical mold and suppressing variation in surface resistivity.

  Therefore, the present invention has been intensively studied on a method for producing a semiconductive seamless belt in order to achieve the above object. As a result, the present inventors have found that the above object can be achieved by the following production method, and have completed the present invention.

That is, the seamless belt manufacturing method of the present invention is a seamless belt manufacturing method in which a resin solution is spread on the inner surface of a cylindrical mold, and the mold is heated by induction heating to heat mold the resin solution. And
The outer and inner surfaces of the mold are plated with a magnetic material or a non-magnetic material.

  The operational effects of the above configuration are as follows. A conductive filler for imparting conductivity is blended in the raw material resin of the seamless belt. This resin solution is applied to the inner surface of the cylindrical mold and developed on the inner surface. Next, the coating film is made uniform by rotating the mold. The mold is then heated by induction heating. As a method of induction heating, for example, a known induction heating device can be applied. When the mold is heated by induction heating, the resin solution developed on the mold is heated. Here, in order to heat uniformly, it controls so that a metal mold | die or an induction heating apparatus may be rotated and a metal mold | die may be heated uniformly. As a result, it is preferable because the heating time is not partly increased and the heating temperature is not partially increased.

  The outer peripheral surface and inner peripheral surface of the mold are plated with a magnetic material or a non-magnetic material. As a result, the mold is heated more uniformly. By the plating process, the heating temperature of the mold becomes uniform, and the heating temperature does not partially increase or decrease.

  As a result, uniform heating can be performed in the thickness direction of the resin film applied to the mold, and the surface resistance does not cause significant aggregation until the uniformly dispersed conductive filler is deposited on the belt. It is possible to manufacture a seamless belt in which variation in rate and reduction in electric resistance value are suppressed. The obtained seamless belt is useful as an intermediate transfer belt used in an image forming apparatus, and the seamless belt manufacturing method of the present invention is useful as an intermediate transfer belt manufacturing method used in an image forming apparatus.

  As a preferred embodiment of the present invention, the thickness variation of the plating layer applied to the mold is within ± 20% of the average thickness of the plating layer. It is preferable that the variation in the plating layer is small because the mold can be heated uniformly.

  In addition, the present invention is a polyimide resin that is particularly suitable for thermosetting and high-viscosity resins, and that can take advantage of excellent properties such as heat resistance, mechanical strength, and chemical stability from the viewpoint of use. It can be said that the production method is very suitable for finishing into a seamless belt excellent in uniformity of surface resistivity while being dried and molded in a short time. The seamless belt obtained by the production method of the present invention is excellent as a functional belt such as a transfer conveyance belt, an intermediate transfer belt, a transfer fixing belt, and a photoreceptor belt of a copying machine or a printer, and is used in a wide range of other fields. Deployment is also possible.

  As a preferred embodiment of the present invention, the distance between the recording die and the induction coil for heating can be adjusted.

  This makes it possible to easily cope with various conditions such as the thickness of the belt and the pipe diameter of the mold, which can be changed in the manufacturing process, by arbitrarily enabling the optimal heating arrangement, and within one process. By making it possible to cope with changes in conditions, it is possible to make finer adjustments.

As an example of a preferred embodiment of the method of the present invention,
A cylindrical mold for producing a seamless belt;
Means for spreading a resin solution on the inner surface of the cylindrical mold;
Means for heating and molding the resin solution by heating the cylindrical mold by induction heating, and a seamless belt manufacturing apparatus comprising:
The outer and inner surfaces of the cylindrical mold are plated with a magnetic or non-magnetic material.

  The operational effects of this configuration are the same as the operational effects described above.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate.

  The present invention is a seamless belt manufacturing method and a manufacturing apparatus therefor, in which a resin solution is spread on the inner surface of a cylindrical mold subjected to plating, and rotational molding and heat molding are performed. Then, the resin film is heated by heating the mold by induction heating, and a highly uniform seamless belt is manufactured.

  The present invention is capable of heating without being in direct contact with the object to be heated (resin film), and can directly input electric energy to the object to be heated, and has the advantages that temperature control is easy and quick. Thus, the rotating mold itself is heated uniformly without contact. And it discovered that the uniform belt with the high uniformity of the thickness can be ensured by performing uniform heating also to the thickness direction of the resin film applied to the metallic mold.

  In addition, according to the semiconductive seamless belt manufacturing method comprising the above steps, no significant aggregation occurs until the uniformly dispersed conductive filler is formed into a belt. For this reason, variations in surface resistivity and a decrease in electrical resistance value can be suppressed. For example, the use of an imidization accelerator can provide a seamless belt excellent in temperature and environmental flexibility and surface smoothness.

  In addition, the production method of the present invention makes it possible to produce a seamless belt excellent in uniformity of surface resistivity, which is useful for an intermediate transfer belt used in an image forming apparatus.

<Mold>
As the material of the cylindrical mold, a heat resistant material such as stainless steel (SUS), aluminum (AI), or carbon steel is used. The size (inner diameter, outer diameter, height) of the cylindrical mold is not particularly limited, and can be set depending on the size of the seamless belt.

(Plating treatment)
Examples of the plating material applied to the cylindrical mold include zinc, nickel, a composite of nickel and chromium, hard chromium, Teflon (registered trademark), and anodized (when the mold material is aluminum or aluminum alloy). Particularly, electroless nickel plating of magnetic material, chromium of nonmagnetic material, etc. can be suitably applied. Plating treatment is preferably performed on the entire surface of the mold, and at least the inner peripheral surface, or the inner peripheral surface and the outer peripheral surface are preferably applied. The plating method is required to suppress variation in the thickness of the plating layer, and a known processing method capable of realizing this can be applied.

The thickness of the plating applied to the cylindrical mold is, for example, 100 μm or less for a magnetic material, and about 10 to 30 μm for a nonmagnetic material, although it varies depending on the permeability of the mold material and the nonmagnetic material. For example, the permeability is 3.142 × 10 ⁻³ (H / m) for carbon steel, and the permeability is 1.257 × 10 ⁻⁶ (H / m) for hard chromium. Further, the plating thickness variation is within ± 20% of the average thickness, preferably within ± 10%, and particularly preferably within ± 5%.

<Manufacturing method / apparatus>
(Induction heating method and equipment)
FIG. 1 is an explanatory view showing an outline of a manufacturing method and apparatus showing an example of the present invention. A heating induction coil 2 is installed at a predetermined distance from a cylindrical mold 1 that spreads the resin solution on the inner surface. When a high frequency current is applied from the high frequency power source 4 to the heating induction coil 2, an induction current is generated in the cylindrical mold 1 and heat is generated by the internal resistance, that is, the cylindrical mold 1 itself is heated. At this time, if the current value to be applied is changed, the generated induced current also changes and the amount of heat generation also changes, so that the heating amount can also be varied. As shown in the lower part of FIG. 1, the cylindrical mold 1 can be rotated at a predetermined number of rotations by a rotating roller 3 provided in contact with the mold 1. Realized operation state (that is, stop, high speed rotation (for example, about 5 to 100 rpm, 100 rpm or more), low speed rotation (for example, if high speed rotation is 5 rpm or more, low speed rotation is less than 5 rp), etc.) .

  In addition, it is preferable that the distance between the mold and the heating induction coil 2 can be adjusted. That is, as described above, the heating amount of the cylindrical mold 1 in FIG. 1 can be controlled by the induced current, but the distance at which the heating induction coil 2 is installed with respect to the cylindrical mold 1 can be adjusted. Thus, the control range can be further expanded and applied to various uses. That is, depending on the shape and material of the mold, the control range by the induced current may be limited, and the present invention can be a very effective means in such a case. Similarly, various conditions such as the thickness of the belt and the pipe diameter of the mold can be easily accommodated by enabling the optimal heating arrangement arbitrarily, and within one process. By making it possible to cope with changes in conditions, it is possible to make finer adjustments.

(Induction coil for electromagnetic heating)
The heating induction coil 2 is not particularly limited as long as it exhibits an electromagnetic induction function, and examples thereof include a face-fired coil, a square coil, a cylindrical heating coil, and the like, along the axial direction of the cylindrical mold. In the case of heating, a square coil and a face-fired coil are preferable. Further, when heating the entire inner surface of the cylindrical mold, a cylindrical heating coil is preferable.

(Coating method / apparatus)
The method / means for forming the resin film on the inner surface of the cylindrical mold is not particularly limited, and a conventionally known method / means can be applied. For example, a bullet-shaped traveling body is used to travel at its own speed with a weight of 20 mm / min. Examples include methods and means for running on the inner surface of the mold and applying the resin film to the inner peripheral surface of the mold, and a method of applying the resin film to the inner peripheral surface with a coating apparatus.

  Next, after applying the resin solution to the inner surface of the mold, the mold is rotated at a high speed (for example, 100 rpm) for a predetermined time (for example, several minutes to several tens of minutes) in order to uniformly develop the thickness of the resin film on the inner peripheral surface. To 5000 rpm). The rotation speed and rotation time of the mold are set depending on the viscosity of the resin solution and the like. Next, the mold is heated by induction heating while rotating the mold at a low speed (for example, in a range of greater than 0 rpm to less than about 5 rpm to less than 100 rpm). By heating the mold, the mold heats the resin film.

  By using induction heating, the cylindrical mold is heated, the solution is evaporated, and the thermal efficiency is improved as compared with the conventional method, so that a dry film can be realized in a short time. In particular, since plating is performed uniformly while suppressing thickness variation, the amount of heat transferred from the mold surface to the resin solution is uniform in the mold axis direction, and the surface resistivity of the dry film does not vary.

(Conductive filler)
The carbon black used in the present invention has an average particle size of 5 to 100 nm, preferably 10 to 70 nm, and more preferably 15 to 60 nm. Those having an average particle diameter of less than 5 nm are substantially difficult to obtain. When the average particle diameter exceeds 100 nm, the surface roughness, mechanical strength and electrical properties of the polyimide resin composition containing the carbon black This is because it is difficult to obtain a practically satisfactory one from the viewpoint of resistance controllability.

  The said average particle diameter shows the average particle diameter based on the primary particle diameter measured with the electron microscope etc. In addition, the carbon black may have its electric resistance controlled by grafting a polymer on the particle surface or coating an insulating material, or may oxidize the carbon black particle surface. Examples of the carbon black used in the present invention include furnace black and channel black. Specifically, “Special Black 550”, “Special Black 350”, “Special Black 250”, “Special Black 100”, “Printex 35”, “Printex 25”, manufactured by Mitsubishi Chemical Corporation, manufactured by Degussa Huls, Inc. “MA77”, “MA8”, “MA11”, “MA100”, “MA100R”, “MA220”, “MA230”, manufactured by Cabot Corporation, “MONARCH 1300”, “MONARCH 1100”, “MONARCH 1000”, “MONARCH 900” ”,“ MONARCH 880 ”,“ MONARCH 800 ”,“ MONARCH 700 ”,“ MOGUL L ”,“ REGAL 400R ”,“ VULCAN XC- “Color B1ack FW200”, “Color B1ack FW2”, “Color B1ack FW2V”, “Color B1ack FW1”, “Color B1ack FW18”, “Color B1ack FW18”, “Color B1ack FW18”, “Color B1ack FW18” “ColorBlackS170”, “ColorBlackS160”, “SpecialBlack5”, “SpecialBlack4”, “SpecialBlack 4A”, “Printex 150T”, “Printex U”, “Pex”, “Tex”, “Pex” A single type or a plurality of types of carbon black may be used in combination.

(Resin solution raw material)
The organic polar solvent used in the present invention is not particularly limited as long as it enhances the dispersibility of the conductive filler, particularly carbon black, but N, N-dialkylamides are useful. N-dimethylformamide, N, N-dimethylacetamide and the like can be mentioned. They can be easily removed from the polyamic acid and the polyamic acid molded article by evaporation, displacement or diffusion. Other organic polar solvents include N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine , Tetramethylene sulfone, dimethyltetramethylene sulfone and the like. These may be used singly or a known method can be applied as a dispersion method, and examples thereof include a pole mill, a sand mill, a basket mill, and ultrasonic dispersion.

  Next, in order to prepare a semiconductive polyamic acid solution, diamine and acid dianhydride are dissolved in an organic polar solvent, and the carbon black dispersion is added to the polyamic acid solution obtained after the polymerization reaction. A method of mixing and stirring, a method of dissolving a diamine and an acid dianhydride in the carbon black dispersion, and a polymerization reaction, etc. are mentioned. In order to make the dispersibility of carbon black uniform, the latter method is used. preferable.

  As the acid dianhydride component, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride Perylene-3,4,9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride and the like.

Examples of the diamine include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl-4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine, 3,3 ′ -Dimethoxybenzidine, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylpropane, 2,4-bis (β-amino-t-butyl) toluene, bis (p -Β-amino-t-butylphenyl) ether, bis (p-β-methyl-t-aminophenyl) Benzyl) benzene, bis-p- (1,1-dimethyl-5-amino-pentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di ( p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2 , 11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylno Methylenediamine, 2,11-diaminododecane, 2,17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 1,12-diaminooctadecane, 2,2- Bis [4- (4-aminophenoxy) phenyl] propane, piverazine, H ₂ N (CH ₂ ), O (CH ₂ ) ₂ OCH ₂ NH ₂ , H ₂ N (CH ₂ ) ₃ S (CH ₂ ) ₃ NH ₂ , H ₂ N (CH ₂ ) ₃ N (CH ₂ ) ₂ (CH ₂ ) ₃ NH _{2 and the} like.

  An appropriate solvent can be used for the polymerization reaction of these acid dianhydrides and diamines, but an organic polar solvent is preferably used from the viewpoint of solubility and the like, and for the dispersion of carbon black and the solvent for the polymerization reaction. Those that can also be used together are more preferred.

Regarding the blending amount of each raw material, it is necessary to experimentally examine a composition suitable for the intended use of the finally obtained polyimide resin composition. For example, the addition amount of carbon black for obtaining a semiconductive polyimide belt having a common logarithm of surface resistivity of 8 to 13 (log Ω / □) is preferably about 10 to 40% by weight with respect to the polyimide resin solid content. 10 to 30% by weight is more preferable. In order to develop the resistance region, it is necessary to use a highly conductive carbon black. When such a highly conductive carbon black is added at a low addition amount of less than 10% by weight, a stable resistance can be produced with good reproducibility. May be difficult. On the other hand, if it exceeds 40% by weight, the inherent high mechanical properties of the polyimide resin are impaired, brittleness is developed, and the belt end face may be cracked when the belt is driven by a plurality of drive rollers or the like.

  The monomer concentration (concentration of acid dianhydride component and diamine component in the solvent) of the semiconductive polyamic acid solution is set according to various conditions, but is preferably 5 to 30% by weight. The polymerization reaction is carried out in a nitrogen atmosphere, the reaction temperature is preferably set to 60 ° C. or less, and the reaction time is preferably about 0.5 to 10 hours. The semiconductive polyamic acid solution can be adjusted in viscosity because the solution viscosity increases as the polymerization reaction proceeds. Also, the viscosity can be adjusted by lowering the monomer concentration by adding a solvent or the like. The viscosity of the semiconductive polyamic acid solution in the present invention is usually 1 to 1000 Pa · s.

  As a method for obtaining a semiconductive polyamic acid solution, carbon black is dispersed in an organic polar solvent in the presence of a polymer dispersant to obtain a carbon black dispersion, and the polyamic acid is polymerized in the carbon black dispersion. A method of obtaining a uniform semiconductive polyamic acid solution by adding an imidization accelerator to a semiconductive polyamic acid solution, mixing and stirring, or carbon black in an organic polar solvent in the presence of a polymer dispersant A method of obtaining a uniform solution by adding an imide conversion catalyst to a semiconductive polyamic acid solution in which the carbon black dispersion and the polyamic acid are mixed, and mixing and stirring. However, according to the production method of the present invention, the mechanical strength and elasticity are further satisfied, and the flexibility of temperature and environment is improved. It is possible to provide a seamless belt having excellent surface smoothness. In other words, the production method of the present invention can greatly reduce the occurrence of mixing unevenness and foam mixing due to the mixing and stirring time and method, improve the uniformity of carbon black dispersion, Protrusions can be prevented and high film thickness accuracy can be ensured.

  The seamless belt obtained by the above manufacturing method is excellent as a functional belt such as transfer and transfer belts for copying machines and printers, intermediate transfer belts, transfer and fixing belts, and photoreceptor belts, and can be used in a wide range of other fields. Is possible. Moreover, it cannot be overemphasized that the drying method and this invention of this invention can be applied not only to the seamless belt of the said use but to the belt used for every field | area, and are not limited above.

<Example>
Examples and the like specifically showing the configuration and effects of the present invention will be described below. Evaluation items in Examples and the like were measured as follows. In addition, this invention is not limited to this Example and evaluation method.

<Evaluation method>
(1) Surface resistivity and its variation Hiresta UP, MCP-HTP16 (manufactured by Mitsubishi Chemical Corporation, probe: UR-100) Applied voltage 100V, 10 seconds later, surface resistivity at measurement conditions 25 ° C., 60% RH The surface resistivity was shown as a common logarithm value. Measure 12 locations for each sample (4 locations in the circumferential direction and 3 points in the axial direction = 12 locations), and the deviation between the maximum and minimum values in the circumferential and axial directions (maximum value / minimum value) The variation in surface resistivity was evaluated. The average value is also calculated.

(2) Thickness of plating and its variation With an electromagnetic digital film thickness meter (SDM-3000, Sanko Electronics Laboratory Co., Ltd.), the average value of the thickness plated on the mold and the thickness variation (%) evaluated. The thickness variation is calculated by (maximum value−average value) ÷ average value × 100.

<Example>
In a mixed solution of 1687 g of N-methyl-2-pyrrolidone (NMP) and 163 g of isoquinoline, 200 g of carbon black (MA1O0, manufactured by Mitsubishi Chemical Corporation, furnace black, average particle diameter 22 nm based on primary particles) and poly (N-vinyl-2) -Pyrrolidone) 100 g was added. After being dispersed by stirring at room temperature for 12 hours using a ball mill, it was filtered through a # 400 stainless steel mesh to obtain a carbon dispersion having a carbon concentration of 10%. 192.39 g of this carbon dispersion was transferred to a 5000 ml four-necked flask, and 2040.13 g of N-methyl-2-pyrrolidone and 227.09 g (2.1 mol) of p-phenylenediamine were charged and dissolved while stirring at room temperature. did. Next, 617.86 g (2.1 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added, reacted at 20 ° C. for 1 hour, and then heated at 75 ° C. for 20 hours. By stirring the mixture, a carbon black-containing polyimide precursor solution having a solution viscosity of 150 Pa · s as measured by a B-type viscometer (solid content concentration 20 wt%, carbon black addition amount resin 25 parts) was obtained. This carbon black-containing polyimide precursor solution was filtered using a # 800 stainless steel mesh to obtain a varnish for forming a semiconductive polyimide belt. Next, the semiconductive polyimide belt forming varnish is dispensed by a dispenser with an outer diameter of 320 mm, a length of 1200 mm, a hard chrome plating thickness average value of 14.1 μm, and a maximum plating thickness variation of 4.3% (on the inner and outer peripheral surfaces). It was applied to the inner peripheral surface of a metal cylindrical mold (plated) so as to have a thickness of 600 μm. Next, after rotating for 10 minutes at 1500 rpm on a rotary molding machine to form a uniform thickness layer, the mold is heated to 345 ° C. by induction heating while rotating at 10 rpm to remove the solvent and dehydrated ring-closing water. And imide conversion. Thereafter, the temperature was returned to room temperature to obtain a seamless semiconductive belt having a thickness of 77 to 78 μm.

<Comparative Example 1>
The metal cylindrical mold of the example was replaced with a mold having a hard chrome plating thickness average value of 24.6 μm and a maximum plating thickness variation of 36.7%.

<Comparative example 2>
The metal cylindrical mold of the example was replaced with a mold having a hard chrome plating thickness average value of 280 μm and a maximum plating thickness variation of 12.6%.

Table 1 shows a comparison when each mold is used.

  From the results of Table 1, in the example, compared with Comparative Examples 1 and 2, by using an induction heating method using a mold having a thin plating thickness (average value) and small thickness variation, the surface resistivity is reduced. A seamless belt made of polyimide resin with little variation was obtained.

  Based on the above, the production method of the present invention is suitable for thermosetting and high-viscosity resins, and particularly suitable when the resin solution is a solution containing a polyamic acid solution as a main component. Polyimide resin that can make use of properties such as heat resistance, mechanical strength, and chemical stability from the application aspect, is finished in a seamless belt that is dried and molded in a short time and has no variation in surface resistivity. It can be said that this is a very suitable manufacturing method.

  The seamless belt obtained in this way is excellent as a functional belt such as transfer and transfer belts for copying machines and printers, intermediate transfer belts, transfer and fixing belts, and photoreceptor belts, and can be used in a wide range of other fields. It is.

Explanatory drawing which shows an example of the apparatus for enforcing the method concerning this invention

Explanation of symbols

1 Cylindrical mold 2 Induction coil for heating 3 Rotating roller 4 High frequency power supply

Claims (6)

A method for producing a seamless belt, in which a resin solution is developed on the inner surface of a cylindrical mold, and the mold is heated by induction heating, and the resin solution is thermoformed.
The outer surface and inner surface of the mold are plated with a magnetic or non-magnetic material ,
The plating thickness of the magnetic material is 100 μm or less, and the variation in plating thickness is within ± 20% of the average plating thickness,
A method for producing a seamless belt, wherein the plating thickness of the non-magnetic material is in the range of 10 to 30 μm and the variation in plating thickness is within ± 20% of the average plating thickness . The method for producing a seamless belt according to claim 1, wherein the plating contains chromium, and variation in plating thickness is within ± 10% of an average plating thickness .   The method for producing a seamless belt according to claim 1, wherein the resin solution is a solution containing a polyamic acid solution as a main component.   The method for manufacturing a seamless belt according to any one of claims 1 to 3, wherein a distance between the mold and the induction coil for heating is adjustable. Cylindrical mold for manufacturing a seamless belt, means for spreading a resin solution on the inner surface of the cylindrical mold, and means for thermoforming the resin solution by heating the cylindrical mold by induction heating A seamless belt manufacturing apparatus comprising:
The outer surface and the inner surface of the cylindrical mold are plated with a magnetic or non-magnetic material ,
The plating thickness of the magnetic material is 100 μm or less, and the variation in plating thickness is within ± 20% of the average plating thickness,
An apparatus for producing a seamless belt, wherein the plating thickness of the non-magnetic material is in the range of 10 to 30 μm and the variation in plating thickness is within ± 20% of the average plating thickness . The seamless belt manufacturing apparatus according to claim 5, wherein the plating contains chromium, and variation in plating thickness is within ± 10% of an average plating thickness.

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